dto

Using this implementation instead of the starlite.SQLAlchemy plugin DTO as a POC for using the SQLAlchemy model type annotations to build the pydantic model.

Also experimenting with marking columns for DTO purposes using the SQLAlchemy.Column.info field, which allows demarcation of fields that should always be private, or read-only at the model declaration layer.

Mode

Bases: Enum

For marking column definitions on the domain models.

Example

class Model(Base):
    ...
    updated_at: Mapped[datetime] = mapped_column(info={"dto": Mode.READ_ONLY})

Purpose

Bases: Enum

For identifying the purpose of a DTO to the factory.

The factory will exclude fields marked as private or read-only on the domain model depending on the purpose of the DTO.

Example

ReadDTO = dto.factory("AuthorReadDTO", Author, purpose=dto.Purpose.READ)

factory

factory(name, model, purpose, exclude=None)

Create a pydantic model class from a SQLAlchemy declarative ORM class.

The fields that are included in the model can be controlled on the SQLAlchemy class definition by including a "dto" key in the Column.info mapping. For example:

```python
class User(DeclarativeBase):
    id: Mapped[UUID] = mapped_column(
        default=uuid4, primary_key=True, info={"dto": dto.Mode.READ_ONLY}
    )
    email: Mapped[str]
    password_hash: Mapped[str] = mapped_column(info={"dto": dto.Mode.PRIVATE})
```

In the above example, a DTO generated for Purpose.READ will include the id and email fields, while a model generated for Purpose.WRITE will only include a field for email. Notice that columns marked as Mode.PRIVATE will not have a field produced in any DTO object.

Parameters:

Name	Type	Description	Default
name	str	Name given to the DTO class.	required
model	type[DeclarativeBase]	The SQLAlchemy model class.	required
purpose	Purpose	Is the DTO for write or read operations?	required
exclude	set[str] | None	Explicitly exclude attributes from the DTO.	None

Returns:

Type	Description
type[BaseModel]	A Pydantic model that includes only fields that are appropriate to purpose and not in
type[BaseModel]	exclude.